The range of spectacle lenses offered has become ever greater and more varied in recent years. New materials, production methods, coating and finishing processes enable the manufacturer to offer spectacle lens products that are tailored even more to the individual needs of the customer. The following paragraphs provide a brief overview of the multitude of variants of the products.
While in the past spectacle lenses were predominantly made from mineral glasses, in particular crown glasses (Abbe dispersion number >55) and flint glasses (Abbe dispersion number <50), in the meantime spectacle lenses from a multiplicity of organic materials are available. Typical organic materials are diethylene glycol bisallyl carbonate or allyl diglycol carbonate (ADC), which are sold by the company PPG Industries under the brand name “Columbia Resin 39” or “CR 39”, higher refractive thermosetting polymer materials, such as for example the polythiol urethanes sold under the trade names MR-7, MR-8, MR-10 of the company Mitsui Chemicals (the abbreviation “MR” stands here for “Mitsui Resin”), polymethylmethacrylate (abbreviation: PMMA) or polycarbonate.
Enhanced production engineering capabilities, in particular direct machining by so-called Fast Tool Servo turning machines or milling machines, as are described, for example, in U.S. Pat. No. 6,199,983, make it possible to produce usable optical surfaces even with a highly unsymmetrical form. This necessitates no further working steps, or working steps of a short duration with flat polishing tools, as described, for example, in U.S. Pat. No. 7,588,480. As a result, it is possible to adapt the refractive power distribution of the spectacle lens individually to the needs of the wearer.
Thus, for example, U.S. Pat. No. 5,444,503 discloses the production of spectacle lenses for people with presbyopia from semifinished blanks with a progressive front face, the rear face of which is not only produced on the basis of the prescription values, but also is optimized on the basis of individual conditions of use, such as the corneal vertex distance, object ranges, pantoscopic tilt of the frame, form of the frame, bending and slightly different refraction values for the axis and cylinder in the far and near ranges.
U.S. Pat. No. 6,089,713 describes the production of progressive lenses from semifinished blanks with a spherical or rotationally symmetrically aspherical front face, the rear face of which is produced both on the basis of the prescription values and the addition and which is additionally optimized with regard to individual conditions of use, such as the corneal vertex distance, any aniseikonia, the pantoscopic tilt of the frame, form of the frame, the centering, the pupillary distance, special situations of use, (such as for example screen work, car driving, sport, et cetera) as well as different effects for the right and left eyes, with an effect on the compensation for prismatic side-effects.
Werner Köppen describes in the article “Konzeption and Entwicklung von Progressivgläsern [Design and development of progressive lenses], which appeared in the Deutsche Optikerzeitschrift [German opticians' journal], DOZ 10/95 edition, pages 42 to 46, that physiological requirements are taken into consideration in the design of progressive lenses. Attention is drawn in particular to the measurement of the turning of the head and eyes during car driving and the registration of movements of the eyes and head during office work.
U.S. Pat. No. 6,827,443 describes a system and a method for prescribing and/or dispensing spectacle lenses for a wearer. The method comprises the determination of at least individual visual behavioral patterns with regard to the head movement and/or the eye movements of the wearer as well as the processing of these patterns with respect to a predetermined relationship between known head movement and/or eye movement characteristics and available spectacle lenses in such a way that the processing assigns the wearer to a head movement or eye movement category, which can then be used to issue a recommendation for a spectacle lens for the wearer.
U.S. Pat. No. 6,199,983 B1 also describes an individualization of the refractive power distribution of the spectacle lens for the user. Apart from the aforementioned individual conditions of use, it specifies further optimization parameters, such as the convergence of the eyes, the turning of the eyes, the viewing direction and the face form wrap. The special situations of use are specified by this document on the basis of lifestyle, such as hobbies and occupation. Past preferences and habits of the spectacle wearer are also taken into consideration.
U.S. Pat. No. 7,980,692 concerns the prescribing and/or dispensing of ophthalmic lenses, such as progressive lenses, for a wearer. According to U.S. Pat. No. 7,980,692, usage information is obtained from a wearer and entered into a programmed computer. The programmed computer processes the usage information and provides a specially weighted lifestyle score for each of one or more lifestyle score categories, such that each weighted lifestyle score is a function of a predetermined relationship between the corresponding lifestyle score category and at least one spectacle lens design feature. The programmed computer then selects or designs a spectacle lens design using one or more of the weighted lifestyle scores such that the selected or designed spectacle lens has at least one spectacle lens design feature that has been customized individually to the wearer using one or more of the weighted lifestyle scores.
Enhanced and improved methods and devices for determining defective vision, as are described, for example, in U.S. Pat. No. 7,771,052 or U.S. Pat. No. 7,744,217, also allow an individual adaptation of the refractive power distribution of the spectacle lens to the subsequent wearer. Thus, visual defects of a higher order that become noticeable in particular with wide-opened pupils are taken into consideration.
The optical coating of a spectacle lens may comprise an antireflective coating, a reflective coating, a hard coating, a dirt-repelling coating, a coating preventing or reducing fogging and a coating with an antistatic effect. Finally, there are coatings with a polarizing effect and coatings that produce a desired color impression. Each of these coatings may be formed by one or more individual optically transparent layers. Examples can be taken from the documents U.S. Pat. No. 8,591,026, U.S. Pat. No. 6,852,406 and U.S. Pat. No. 8,425,035.
For optometrists and ophthalmic opticians, known as Eye Care Professionals (shortened to ECPs), this great variety of products and configurational possibilities means that it is increasingly unclear what is being offered overall by the manufacturers. It is therefore increasingly more difficult to select from what they offer the optimum spectacle lens for the customer (note: the term glass is used generally and hereinafter as a synonym for the term lens, even though spectacle lenses made of plastic have by now taken the place of lenses made of mineral glasses in large number on the market) and on the other hand to give the customer a clear idea of the differences between the products.
In the past, the suppliers of spectacle lenses have provided electronic price lists with various filtering functions, which makes searching from the great variety easier. Some manufacturers additionally also offer what are known as consulting tools or demonstrators for spectacle lenses, which are intended to present a visual representation, focusing on the product advantages of specific lens types or lens features, for the customer during a sale. Some manufacturers also offer consulting tools for specific lens types (for example individual progressive lenses), in order to determine the ordering parameters of these spectacle lenses.
U.S. Pat. No. 7,914,148 B2 describes a method and a system for simulating an optical effect and/or characteristic of a selected spectacle lens design for a wearer. This involves retrieving simulation data for the selected spectacle lens design, processing it into image data and displaying it to the spectacle wearer with the aid of a head-mounted display to simulate the optical effect and/or characteristics of the selected spectacle lens design.
The solutions available so far on the market only ever cover a partial aspect of the spectacle lens selection. In particular, aids that take into consideration the inclusion of customer needs and the measured values for the eyes in the specific selection of the spectacle lens, and the variants or special features, are not so far available on the market.